This invention relates to power switch assemblies of the type adapted for in-line mounting with a power line and having one or more end fitting members adapted for pivotal mounting to a clevis member of a strain link and, more particularly, to a device wherein the rotational movement of the switch relative to the strain link is substantially reduced.
In-line switches are known to the overhead power switchgear art and are disposed in mechanical and electrical series with power line conductors in such a manner as to provide part of the mechanical structure of the lines. The switches carry the full current in the power lines when they are closed and provide an effective open circuit in the lines when they are open, thereby to enable electrical isolation of branches of a power distribution system. The usual installation of in-line switches is accomplished with a strain link which is mechanically joined at one of its ends to a standoff insulator and the other end is mounted to an end fitting of the in-line switch. The strain link provides mechanical support between the standoff insulator and the in-line switch. The standoff insulator is mounted to a utility pole to provide both a support point or mounting location for the power line conductor and to insulate the conductor from the pole. In these installations, the end fitting of the in-line switch is pivotally mounted to a clevis member end of the strain link.
Thus, these installations typically include three pivot points, that is: a pivot point where the strain link is mounted to the insulator, the pivotal mounting of the clevis member to the end fitting, and a pivot point where the power line is connected to the other end of the in-line switch. Further, in those installations where a strain link is provided at each end fitting of the in-line switch, at least one additional pivot point results. It has been found that because of these pivot points, excessive or undesirable movement of the in-line switch results during the operation of the switch. Excessive movement can be detrimental to the function of the switch installation and may be a hazard to the lineman or operator. That is, the upward force needed during switch closing can be excessive due to the rotation occurring at the pivot points. This excessive force is necessitated by the undesirable movement of the in-line switch about the pivot points and from the in-line switch being in an abnormally high position with respect to the conductor at the time of closing. Furthermore, since switch operation is normally accomplished with an insulated and somewhat flexible switch stick or "hot stick", which can be 8 feet in length or longer, all excessive movements, and the excessive forces necessitated thereby, should be removed from the installation in order to attain reliable functioning of the in-line switch.
These and other disadvantages are overcome by the present invention wherein a device is provided for reducing or preventing relative rotation between the in-line switch and the strain link or links during the operation of the in-line switch, particularly during closing.